1. Field of the Invention
The present invention relates to an electronics apparatus such as an image forming apparatus that is a heat transfer printer having a heat source, for example, a thermal head including a heat generating part that generates heat when it is operated, wherein, in particular, the heat source and heat generating parts forming a power supply circuit board that supplies electrical power to the heat source can be effectively cooled by a simple structure.
2. Description of the Related Art
As generally known, in electronics apparatuses such as heat transfer printers as image forming apparatuses, electronic parts including a thermal head, a power supply transformer that forms a power supply circuit board for supplying electrical power to the thermal head, a voltage control element such as an electrical field-effect transistor (hereinafter, simply abbreviated as FET), and a coil are known as heat generating parts that generate heat when operating, and it is necessary to effectively cool these.
In consideration of the abovementioned circumstances, conventionally, a structure disclosed (for example, refer to JP-A-2002-321426) in which cooling air is blown by a cooling fan to a cooling chamber having a heat sink provided on the back surface of the thermal head, and a slight amount of cooling air is blown to a fixing part via a tube from the cooling chamber.
However, in the construction described in JP-A-2002-321426 given above, most of the cooling air from the cooling fan is consumed for cooling of only the thermal head and then exhausted to the outside, and the fixing part is cooled only by a slight amount of cooling air, and the power supply circuit board that has heat generating parts necessary for supply of the electrical power is not cooled at all.
As a countermeasure for this, in the construction of JP-A-2002-321426 given above, for cooling the power supply circuit board, it is necessary that another cooling fan is provided, and this increases components and results in an increase in cost and an increase in size, etc.